Suction device

ABSTRACT

A suction device comprises a first element, a second element, and an intermediate element. The first element comprises a first control volume having a first pressure. The second element comprises a second control volume having a second pressure. The intermediate element is controlled by the first pressure of the first control volume of the first element and the second pressure of the second control volume of the second element. When the first control volume of the first element is varied, the varied first control volume of the first element can substantially have the first pressure under automatic pressure compensation by the second pressure of the second control volume of the second element via the intermediate element.

CROSS REFERENCE TO RELATED APPLICATIONS

This Application claims priority of Taiwan Patent Application No. 099113019, filed on Apr. 26, 2010, the entirety of which is incorporated by reference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention is related to a suction device, especially to a predetermined-pressure suction device which can form a blister on human skin.

2. Description of the Related Art

The inner layer of human skin is dermis consisting of skin appendages such as hair follicles, sebaceous glands, nerves, blood vessels, sweat glands, lymphatic vessels, and fibroblasts which secrete collagen and elastin. The outer layer of the skin is epidermis composed of keratinocytes at different differentiation stages. A basal cell layer is located between the epidermis and dermis. When stress such as friction, heat, or negative pressure is applied on the skin a blister may form which is characterized by tissue fluid built between the epidermis and dermis. A blister can be induced on purpose for medical applications including extracting the blister fluid for biochemical analyses, obtaining the blister roof for an epidermal graft, isolating cells from blister roof for cell therapy, or administering medicines directly on the dermis. A common way to induce a blister with negative pressure (so-called “suction-blistering”) is covering the skin with a suction vessel and then applying a predetermined negative pressure (generally 150-400 mmHg, for example) until the blister is formed (about 1 to 4 hours). During the procedure of generating negative pressure, all of the openings of the suction vessel should be closed, and the appliance for generating negative pressure is switched on until the pressure in the suction vessel reaches a predetermined level. Then, the negative pressure-generating appliance may be turned off or left on until the blister forms within the suction plate (the part that directly attaches to the skin). However, a little amount of air may leak into the suction vessel, reducing the negative pressure, because of the unstable sealing between the suction plate and the skin. Therefore, if the negative pressure-generating appliance is switched off, a pressure gauge is usually connected to the suction vessel for frequent monitoring of the pressure. When reduction of negative pressure is detected, the negative-pressure generating appliance is switched on again to regain the pressure. Without frequent checking at the pressure gauge, leakage will not be detected until hours later when the blister fails to form. Note that adding the pressure gauge increases costs and manual checking and adjusting pressure consumes additional labor. If the negative-pressure generating appliance (an air-extracting motor, for example) is left on continuously a constant pressure can be automatically maintained for hours. However, with the appliance running for hours, the noise can be annoying, the energy consumption is high, and the wear and the occupancy of the appliance are high, which are disadvantages.

BRIEF SUMMARY OF THE INVENTION

The suction device of the invention can be applied to blister formation on a skin surface, negative pressure wound therapy, cupping therapy, blood drawing, biopsy, and drawing fluid of a human body from a skin surface (for example, milk, pus, and wound discharge). In addition to being inexpensive, having a simple structure, being easy to operate, being disposable, and not requiring power, the suction device of the invention can automatically adjust the negative pressure to the predetermined level in case of a little air leakage.

The suction device of the invention includes a first element, a second element, and an intermediate element. The first element includes a first control volume having a first pressure. The second element includes a second control volume having a second pressure. The intermediate element is controlled by the first pressure of the first control volume in the first element and the second pressure of the second control volume in the second element. When the first control volume of the first element is varied to a varied first control volume, automatic pressure compensation on the varied first control volume happens according to the second pressure of the second control volume in the second element via the intermediate element, so that the varied first control volume of the first element has the first pressure, substantially.

The ratio of the first pressure of the first control volume in the first element to the second pressure of the second control volume in the second element is a predetermined ratio. The second control volume of the second element is varied to a varied second control volume after the automatic pressure compensation, and the predetermined ratio of the first pressure of the varied first control volume in the first element to the second pressure of the varied second control volume in the second element is maintained.

The suction device of the invention further includes a suction plate, communicated with the first control volume or the varied first control volume of the first element. The first pressure of the first control volume in the first element or the first pressure of the varied first control volume in the first element produces a suction action on an object via the suction plate.

The present invention further provides a suction device. The suction device includes a first element, a second element, and an intermediate element. The first element includes a first container. The second element includes a second container. The intermediate element includes a first action end and a second action end, both of which are disposed in the first container and the second container, respectively. When the second element is moved relatively to the first element, a first control volume is formed in the first container between an end of the first element and the first action end of the intermediate element, and a second control volume is formed in the second container between an end of the second element and the second action end of the intermediate element. The first control volume in the first container of the first element has a first pressure, the second control volume in the second container of the second element has a second pressure, and the ratio of the first pressure to the second pressure is a predetermined ratio. When one of the second control volume in the second container of the second element and the first control volume in the first container of the first element is varied, automatic pressure compensation happens on the other one. Therefore, the varied first control volume in the first container of the first element has the first pressure, the varied second control volume in the second container of the second element has the second pressure, and the predetermined ratio of the first pressure to the second pressure is maintained.

The predetermined ratio is the ratio of a second sectional area of the second action end of the intermediate element to a first sectional area of the first action end of the intermediate element.

The suction device further includes a suction plate, communicated with the first container of the first element or the second container of the second element. The first pressure of the first control volume or the varied first control volume in the first container of the first element or the second pressure of the second control volume or the varied second control volume in the second container of the second element produces a suction action on an object via the suction plate.

The present invention further provides a suction device. The suction device includes a first element, a second element, and an intermediate element. The first element includes a first container. The second element includes a second container communicated with the first container of the first element. The intermediate element includes a first action end and a second action end, both of which are disposed in the first container and the second container, respectively. When the second element is moved relatively to the first element, a first control volume is formed in the first container between an end of the first element and the first action end of the intermediate element, and a second control volume is formed in the second container between an end of the second element and the second action end of the intermediate element. The first control volume in the first container of the first element has a first pressure, the second control volume in the second container of the second element has a second pressure, and the ratio of the first pressure to the second pressure is a predetermined ratio. When the second control volume in the second container of the second element is varied, automatic pressure compensation happens on the first control volume in the first container of the first element. Therefore, a varied first control volume in the first container of the first element has the first pressure, a varied second control volume in the second container of the second element has the second pressure, and the predetermined ratio of the first pressure to the second pressure is maintained.

The predetermined ratio described above is the ratio of a second sectional area of the second action end of the intermediate element to a first sectional area of the first action end of the intermediate element.

The suction device of the invention further includes a suction plate and a valve element. The valve element is disposed between the first control volume of the first container of the first element and the suction plate. The suction plate is communicated with the first control volume in the first container of the first element. The first pressure of the first control volume in the first container of the first element produces a suction action on an object via the suction plate.

DESCRIPTION OF THE DRAWINGS

The present invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:

FIG. 1A is a schematic view illustrating a suction device in accordance with a first embodiment of the invention.

FIG. 1B is an exploded view illustrating the suction device of FIG. 1A.

FIGS. 2A, 2B, and 2C are views illustrating a process for producing a negative pressure between the second element 2 a and the intermediate element.

FIGS. 3A, 3B, 3C, and 3D are views illustrating a process of forming a bulge on an object with the suction device of the invention.

FIG. 4A is a section view which is cut from the engaging structure L of the suction device of the invention along a line a-a in FIG. 3B during the assembly procedure.

FIG. 4B is a section view which is cut from the engaging structure L of the suction device Ma of the invention along a line b-b in FIG. 3C after the assembly procedure.

FIGS. 5A, 5B, and 5C are views illustrating a process of forming a bulge on an object with the suction device of the invention.

FIGS. 6A, 6B, 6C, and 6D are views illustrating a process of forming a bulge on an object with the suction device of the invention.

FIG. 7 is a view illustrating a suction device which is a variation in accordance with the suction device of the first embodiment in the invention.

FIG. 8 is a view illustrating a suction device in accordance with a second embodiment of the invention.

DESCRIPTION OF THE INVENTION

The following description is of the best-contemplated mode of carrying out the invention. This description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. The scope of the invention is best determined by reference to the appended claims.

The suction device of the invention can generate a pressure (for example, a negative pressure) on a surface of an object (for example, human skin), and then, by the pressure, suck the surface of the object to achieve a particular effect (for example, forming a blister between the epidermis and dermis). To explain the invention easily, the structure of the elements concerned with the suction device of the invention in the drawings are presented in a cross-section view, and the related operation proceeds in the environment set to one atmosphere (1 ATM). It is noted that although the operation environment in the following embodiments is set to one atmosphere, people who are skilled in the art should know that there are different pressure conditions in different environments and the environment should not be limited to one atmosphere.

FIG. 1A is a schematic view illustrating a suction device Ma in an initiate state in accordance with a first embodiment of the invention. FIG. 1B is an exploded view illustrating the suction device Ma of FIG. 1A.

As shown in FIG. 1A and FIG. 1B, the suction device Ma includes a first element 1 a, a second element 2 a, an intermediate element T, a suction plate 3, a valve element 4, and a cover 5.

The first element 1 a includes a first body 10 a, a first opening 101, a second opening 102, and a plurality of first flanges 10 f. The first body 10 a is provided with a first container 100, a first end 10 e 1, a second end 10 e 2, two bottoms 100 b 1, 100 b 2, and a hollow cylinder with an inner diameter D1. The first opening 101 and the second opening 102 are formed at the first end 10 e 1 and the second end 10 e 2 of the first body 10 a, respectively, communicated with the first container 100. A plurality of the first flanges 10 f are disposed on the first body 10 a, adjoining the second opening 102.

The second element 2 a includes a second body 20 a, an opening 201, and a plurality of second flanges 20 f. The second body 20 a is provided with a second container 200, a first end 20 e 1, a second end 20 e 2 (a closed end), and a hollow cylinder with an inner diameter D2. The second end 20 e 2 is a closed end. The opening 201 is formed at the first end 20 e 1 of the second body 20 a, communicated with the second container 200. A plurality of the second flanges 20 f are disposed on the second body 20 a, adjoining the opening 201. The inner diameter D2 of the second body 20 a of the second element 2 a is smaller than the inner diameter D1 of the first body 10 a of the first element 1 a. A plurality of the second flanges 20 f of the second element 2 a and a plurality of the first flanges 10 f of the first element 1 a constitute an engaging structure L (the details will be described with FIGS. 3B, 3C, 4A, and 4B).

The intermediate element T includes a shaft H0, a first action end H1 with a first sectional area A1, and a second action end H2 with a second sectional area A2. The first action end H1 and the second action end H2 are disposed on the shaft H0, interacting via the connection of the shaft H0. As shown in FIG. 1A, the first action end H1 of the intermediate element T is disposed in the first container 100 via the second opening 102 of the first element 1 a, and is contacted with the inner wall 100 s of the first body 10 a of the first element 1 a in a slidable manner, so that the first action end H1 of the intermediate element T can be moved back and forth along the inner wall 100 s of the first body 10 a of the first element 1 a. On the other hand, the second action end H2 of the intermediate element T is disposed in the second container 200 via the opening 201 of the second element 2 a, and is contacted with the inner wall 200 s 1 of the second body 20 a of the second element 2 a in a slidable manner. Also, the first end 20 e 1 of the second element 2 a is installed in the first container 100 of the first body 10 a of the first element 1 a via the second opening 102 of the first element 1 a. In this embodiment, the intermediate element T is a piston element in which the first action end H1 and the second action end H2 are two piston ends with different sizes. The first sectional area A1 of the first action end H1 is larger than the second sectional area A2 of the second action end H2.

The suction plate 3 is a hollow cylinder structure (for example, formed by rubber or other soft materials) including a body 30, a ring-like flange 31, a first opening 301, and a second opening 302. The first opening 301 and the second opening 302 are formed at two sides of the body 30 respectively. The flange 31 is disposed on the peripheral of the body 30.

The valve element 4 including three connection ports 41, 42, and 43 is disposed between the first element 1 a and the suction plate 3. The valve element 4 is used to control flow of a working fluid (for example, air) in the first element 1 a and the suction plate 3. The connection ports 41 and 42 are connected to the first opening 101 of the first element 1 a and the second opening 302 of the suction plate 3, respectively. The cover 5 can be rotated to open or close the connection port 43 of the valve element 4. In the embodiment, the valve element 4 is a T type three-direction valve element.

Note that for the suction device Ma in an initiate state (as shown in FIG. 1A), the second action end H2 of the intermediate element T is moved to the bottom 200 b of the second container 200 of the second body 20 a of the second element 2 a, the first action end H1 of the intermediate element T is moved to the bottom 100 b 1 of the first container 100 of the first body 10 a of the first element 1 a, and the second container 200 of the second element 2 a is communicated with the first container 100 of the first element 1 a.

FIGS. 2A, 2B, and 2C are views illustrating a process for producing a negative pressure (for example, one ATM) between the second element 2 a and the intermediate element T.

As shown in FIG. 2A, the second action end H2 of the intermediate element T is moved to the bottom of the second container 200 of the second body 20 a along a direction from the first end 20 e 1 of the second element 2 a to the second end 20 e 2 of the second element 2 a (namely to the bottom 200 b). At this time, the second action end H2 of the intermediate element T and the second element 2 a are stuck together, and there is no air or just a little air between them.

As shown in FIGS. 2B and 2C, when a force F1 (a pull force) is applied to the first action end H1 of the intermediate element T, the second action end H2 of the intermediate element T is moved from the second end 20 e 2 of the second element 2 a to the first end 20 e 1 of the second element 2 a at a distance of x1 and x2. At the time, the second container 200 of the second body 20 a of the second element 2 a in FIGS. 2B and 2C will form two different control volumes CVb and CVc (shown with dotted line), and the two control volumes CVb and CVc have the same negative pressure (about 1 ATM). After the first action element H1 of the intermediate element T is released from the force F1, based on the balance condition under the negative pressure effect caused by the control volume CVb of FIG. 2B or the control volume CVc of FIG. 2C, the second action end H2 of the intermediate element T slides freely toward the second end 20 e 2 of the second element 2 a, with a force about 1 ATM. Finally, the intermediate element T returns to the initiate state shown in FIG. 2A.

FIGS. 3A, 3B, 3C, and 3D are views illustrating a process (no air leakage happens between the suction plate 3 and the object W) of forming a bulge w0 on an object W with the suction device Ma of the invention.

As shown in FIGS. 3A and 3B, in the case that the connection port 43 of the valve element 4 is sealed with the cover 5, first, the first opening 301 of the suction plate 3 faces the object W and the flange 31 of the suction plate 3 places stress on a particular location of the object W. A force F2 is used to move the second element 2 a relative to the first element 1 a from a first location r21 to a second location r22, and the resulting negative pressure causes suction on the object W to form the bulge w0.

Refer to FIGS. 3B, 3C, 4A, and 4B. FIG. 4A is a section view which is cut from the engaging structure L of the suction device Ma of the invention along a line a-a in FIG. 3B during the assembly procedure. FIG. 4B is a section view which is cut from the engaging structure L of the suction device Ma of the invention along a line b-b in FIG. 3C after the assembly procedure.

It will be understood from the sectional structure of the first element 1 a and the second element 2 a shown in FIG. 4A that the inner wall 100 s of the first element 1 a is opposite to the outer wall 200 s 2 of the second element 2 a, a plurality of the first flanges 10 f of the first element 1 a are spaced at intervals and protrude on the inner wall 100 s of the first body 10 a, and a plurality of the second flanges 20 f of the second element 2 a are spaced at intervals and protrude on the outer wall 200 s 2 of the second body 20 a. Note that although there are three first flanges 10 f and three second flanges 20 f in the embodiment, the number of the flanges of the first element 1 a and the second element 2 a can be adjusted randomly and is not limited threreto.

When the force F2 is used to pull the second element 2 a from the first location r21 to the second location r22, the second element 2 a is moved away from the first element 1 a, and the second element 2 a and the first element la are separated slightly (as shown in FIG. 3B and FIG. 4A). At this time, driven by the second element 2 a simultaneously, the first action end H1 and the second action end H2 of the intermediate element T form a first control volume CV1 having a first pressure P1 in the first container 100 of the first body 10 a of the first element 1 a and a second control volume CV2 having a second pressure P2 in the second container 200 of the second body 20 a of the second element 2 a, respectively. Then the second element 2 a is rotated along a direction R appropriately so that a plurality of the first flanges 10 f of the first element 1 a can overlap a plurality of the second flanges 20 f of the second element 2 a. After that, the force F2 is released. Under the effect of the first control volume CV1 having the first pressure P1 and the second control volume CV2 having the second pressure P2, a plurality of the first flanges 10 f of the first element 1 a and a plurality of the second flanges 20 f of the second element 2 a press against each other (as shown in FIG. 3C and FIG. 4B). Thus, the first control volume CV1 having the first pressure P1 in the first container 100 of the first body 10 a of the first element 1 a makes suction on the object W to form the bulge w0, via the valve element 4 and the suction plate 3. Substantially, when the first element 1 a and the second element 2 a achieve pressure balance, the product of the second pressure P2 of the second control volume CV2 in the second element 2 a and a second sectional area A2 of the second action end H2 is equal to the product of the first pressure P1 of the first control volume CV1 in the first element 1 a and a first sectional area A1 of the first action end H1 (P2×A2=P1×A1). Briefly, when the second pressure P2 of the second control volume CV2 in the second element 2 a and the first pressure P1 of the first control volume CV1 in the first element 1 a achieve balance T, the first pressure P1 of the first control volume CV1 in the first element 1 a will satisfy the following equation.

The first pressure P1 of the first element 1 a=−1 atmosphere×(the second sectional area A2 of the second action end H2/the first sectional area A1 of the first action end H1).

Namely, there is a predetermined ratio between the first pressure P1 of the first control volume CV1 in the first element 1 a and the second pressure P2 of the second control volume CV2 in the second element 2 a. In the embodiment, the predetermined ratio is the ratio of the second sectional area A2 of the second action end H2 to the first sectional area A1 of the first action end H1.

As shown in FIG. 3D, after the suction process (there is no air leakage between the suction plate 3 and the object W during the process) where the suction device Ma is applied on the object W to form the bulge w0 for a while, the air with a negative pressure between the suction plate 3 and the first element 1 a can be released if the cover 5 is removed from the connection port 43 of the valve element 4. Thus, the suction device Ma and the bulge w0 of the object W can be completely separated.

FIGS. 5A, 5B, and 5C are views illustrating a process (there is a little air leakage between the suction plate 3 and the object W during the process and automatic pressure compensation happens) of forming a bulge w0 on an object W with the suction device Ma of the invention.

In the initiate state, the suction device Ma sticks on the object W (as shown in FIG. 5A). During the suction process applied to the object W to form the bulge w0 (the second element 2 a is moved from the first location r21 to the second location r22 as shown in FIG. 5B), if a little air G temporarily leaks into the space between the suction plate and the object W (for example, improper fixation of the object or the suction device Ma makes them fit together imperfectly), the control volume CV1 of the first element 1 a will increase to a varied first control volume CV1′ having a pressure which has decreased. Meanwhile, the second control volume CV2, in the second element 2 a, having the second pressure 2 a becomes a varied second control volume CV2′, because the intermediate element T moves, under automatic pressure compensation to the first control volume CV1 in the first element 1 a. The compensation makes the varied first control volume CV1′ in the first element 1 a still have the first pressure P1. Specifically, because the second pressure P2 of the second control volume CV2 (or the varied second control volume CV2′) is maintained on the same negative pressure (−1 ATM) during the second action end H2 of the intermediate element T freely sliding in the second element 2 a (as described in FIGS. 2B and 2C), when automatic pressure compensation achieves balance, the varied first control volume CV1′ in the first element 1 a has a first pressure P1, and the first pressure P1 of the first control volume CV1′ in the first element 1 a over the second pressure P2 of the second control volume CV2′ in the second element 2 a still maintains the predetermined ratio (the second sectional area A2 of the second action end H2 over the first sectional area A1 of the first action end H1). In other words, when balance is achieved between the first element 1 a and the second element 2 a, the first control volume CV1 in the first element 1 a will be added with a first varied volume ΔV1 and become the varied first control volume CV1′ (that is, the varied first control volume CV1′ is larger than the first control volume CV1), and, correspondingly, the second control volume CV2 in the second element 2 a will be subtracted with a second varied volume ΔV2 and become the varied second control volume CV2′. The ratio of the first varied volume ΔV1 to the second varied volume ΔV2 is substantially equal to the ratio of the first sectional area A1 of the first action end H1 to the second sectional area A2 of the second action end H2 (ΔV1/ΔV2=A1/A2). The varied control volume CV2′ of the second element 2 a has an original pressure value (−1 ATM).

FIGS. 6A, 6B, 6C, and 6D are views illustrating a process (there is a large amount of air leakage between the suction plate 3 and the object W during the process and the process is reset) of forming a bulge w0 on an object W with the suction device Ma of the invention.

In the initiate state, the suction device Ma sticks on the object W (as shown in FIG. 6A). During the suction process applied to the object W to form the bulge w0 (the second element 2 a is moved from the first location r21 to the second location r22 as shown in FIG. 6B), if a large amount of air G leaks into the space between the suction plate 3 and the object W, the first control volume CV1 of the first element 1 a will increase greatly and exceed the load of the volume of the first container 100. Thus, this condition makes the varied first control volume CV1″ in the first element 1 a not maintain a negative pressure (namely, the bulge w0 of the object W loses exertions of the negative pressure as shown in FIG. 6C). Note that in the case that the suction plate 3 and the object W should not need to be separated locally or entirely, the cover 5 can be removed from the connection port 43 of the valve element 4 to make the varied control volume CV1″ in the first element 1 a be communicated with the outside. Then a force F3 is used to push the second element 2 a toward the first element 1 a, which makes the air in the varied first control volume CV1″ in the first element 1 a be released to the outside via the connection port 43 of the valve element 4. Therefore, the suction device Ma can go back to the initiate state (as shown in FIG. 6A) and the suction process of forming a bulge w0 on an object W can be restarted.

Following, related experimental data will be described. Take the suction device Ma, as an example.

It is assumed that the first element 1 a and the second element 2 a are two syringes with volume 20 CC and 5 CC, respectively (both have a location indicating calibration 0) and the first opening 101 of the first element 1 a is connected to a pressure gauge (not shown in figures) for displaying the pressure value. The area ratio of the second action end H2 to the first action end H1 (the second sectional area A2/the first sectional area A1) is 0.426. Thus, producing a negative pressure of 32.4 cmHg can be estimated (76 cmHg×0.426=32.4 cmHg).

After the cover 5 is removed from the connection port 43 of the valve element 4 and the second element 2 a is pushed to the bottom 100 b 1 of the first element la to release the inner air, the connection port 43 of the valve element 4 is sealed again with the cover 5. At this time, the second action end H2 is located at calibration 0 of the second element 2 a; the first action end H1 is located at calibration 0 of the first element 1 a; and the pressure gauge displays that the negative pressure value of the first opening 101 of the first element 1 a is zero.

When the engage structure L is used to position the second element 2 a on the first element 1 a (as shown in FIG. 3C), the second action end H2 is located at calibration 5.5 of the second element 2 a, the first action end H1 is located at calibration 1.8 of the first element 1 a, and the pressure gauge displays that the negative pressure value of the first control volume CV1 of the first element 1 a (or the first opening 101 of the first element 1 a) is −32 cmHg (close to the estimated negative pressure value). When a little air leaks into the first opening 101 of the first element 1 a (as shown in FIG. 5C), the intermediate element T will automatically move toward the second end 20 e 2 of the second element 2 a. When balance is achieved, the second action end H2 is located at calibration 4.4 of the second element 2 a, the first action end H1 is located at calibration 4.5 of the first element 1 a, and the pressure gauge displays that the negative pressure value of the first control volume CV1′ of the first element 1 a is still −32 cmHg. When a little air leaks into the first opening 101 of the first element la again, the intermediate element T will automatically move further toward the second end 20 e 2 of the second element 2 a. When balance is achieved, the second action end H2 is located at calibration 2.7 of the second element 2 a, the first action end H1 is located at calibration 8.6 of the first element 1 a, and the pressure gauge displays that the negative pressure value of the first control volume CV1″ of the first element 1 a is still −32 cmHg.

FIG. 7 is a view illustrating a suction device Ma′ which is a variation in accordance with the suction device Ma of the first embodiment in the invention.

The main difference between the suction device Ma′ and the suction device Ma of the first embodiment is that a latch structure 6 in the suction device Ma′ replaces the engage structure L in the suction device Ma. When a force F2 pulls the second element 2 a to move away from the first element 1 a and the second element 2 a and first element 1 a is separated slightly (similar to the operation of FIG. 3B), the latch structure 6 is used to buckle the second element 2 a on the first element 1 a. The operation of the other elements of the suction device Ma′ is equal to that of the other elements of the suction device Ma of the first embodiment, and are not described again.

FIG. 8 is a view illustrating a suction device Mb in accordance with a second embodiment of the invention.

The main difference between the suction device Mb of the second embodiment and the suction device Ma of the first embodiment is that the suction device Mb of the second embodiment is the suction device Ma of the first embodiment, used inversely.

The suction device Mb includes a first element 1 b, a second element 2 b, an intermediate element T, a suction plate 3, a valve element 4, and a cover 5.

The first element 1 b includes a first body 10 b, an opening 102′, and a plurality of first flanges 10 f. The first body 10 b is a hollow cylinder provided with a first container 100, a first end 10 e 1, a second end 10 e 2, and two bottoms 100 b 1, 100 b 2. The opening 102′ is formed at the second end 10 e 2 of the first body 10 b, and communicated with the first container 100. A plurality of the first flanges 10 f are disposed on the first body 10 b, adjoining the opening 102′.

The second element 2 b includes a second body 20 b, a first opening 201′, a second opening 202′, and a plurality of second flanges 20 f. The second body 20 b is a hollow cylinder provided with a second container 200, a first end 20 e 1, and a second end 20 e 2. The first opening 201′ and the second opening 202′ are formed at the first end 20 e 1 and the second end 20 e 2 of the second body 20 b respectively, communicated with the second container 200. A plurality of the second flanges 20 f are disposed on the second body 20 a, adjoining the first opening 201′. The inner diameter D2 of the second body 20 a of the second element 2 a is smaller than the inner diameter D1 of the first body 10 a of the first element 1 a. A plurality of the second flanges 20 f are disposed on the second body 20 b, adjoining the first opening 201′.

The intermediate element T includes a shaft H0, a first action end H1 with a first sectional area A1, and a second action end H2 with a second sectional area A2. The first action end H1 and the second action end H2 are disposed on the shaft H0, interacting via the connection of the shaft H0. On the other hand, the second action end H2 of the intermediate element T is disposed in the second container 200 via the opening 201′ of the second element 2 b, and is contacted with the inner wall 200 s 1 of the second body 20 b of the second element 2 b in a slidable manner. Also, the first end 20 e 1 of the second element 2 b is inserted in the first container 100 of the first body 10 b of the first element 1 b via the second opening 102′ of the first element 1 b.

The valve element 4 including three connection ports 41, 42, and 43 is disposed between the second element 2 b and the suction plate 3. The valve element 4 is used to control flow of a working fluid (for example, air) in the second element 2 b and the suction plate 3. The connection ports 41 and 42 are connected to the second opening 202′ of the second element 2 b and the second opening 302 of the suction plate 3, respectively. The connection port 43 of the valve element 4 is sealed with the cover 5.

When a force pulls the first element 1 b to move away from the second element 2 b, the first action end H1 and the second action end H2 of the intermediate element T are simultaneously driven by the first element 1 b, so that a first control volume CV1 having a first pressure P1 and a second control volume CV2 having a second pressure P2 are generated in the first container 100 of the first body 10 b of the first element 1 b and in the second container 200 of the second body 20 b of the second element 2 b, respectively. Thus, the second control volume CV2 having the second pressure P2 in the second element 2 b can be used to produce a suction action on an object W to form a bulge w0. When a little air G leaks into the space between the suction plate 3 and the object W temporally, the second control volume CV2 of the second element 2 b increases and the pressure of the second control volume CV2 of the second element 2 b decrease. At this time, automatic pressure compensation on the second control volume CV2 of the second element 2 b according to the first control volume CV1 having the first pressure P1 in the first element 1 b via the movement of the intermediate element T. Therefore, a varied second control volume of the second element 2 b still has the second pressure P2, which can continue the suction action on the object W to form the bulge w0.

While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements. 

1. A suction device, comprising: a first element, comprising a first control volume having a first pressure; a second element, comprising a second control volume having a second pressure; and an intermediate element, controlled by the first pressure of the first control volume in the first element and the second pressure of the second control volume in the second element, wherein when the first control volume of the first element is varied to a varied first control volume, automatic pressure compensation happens on the varied first control volume according to the second pressure of the second control volume in the second element via the intermediate element, so that the varied first control volume of the first element has the first pressure, substantially.
 2. The suction device as claimed in claim 1, wherein the ratio of the first pressure of the first control volume in the first element to the second pressure of the second control volume in the second element is a predetermined ratio, and the second control volume of the second element is varied to a varied second control volume after the automatic pressure compensation, and the predetermined ratio of the first pressure of the varied first control volume in the first element to the second pressure of the varied second control volume in the second element is maintained.
 3. The suction device as claimed in claim 1, further comprising: a suction plate, communicated with the first control volume or the varied first control volume of the first element, wherein the first pressure of the first control volume in the first element or the first pressure of the varied first control volume in the first element produces a suction action on an object via the suction plate.
 4. A suction device, comprising: a first element, comprising a first container; a second element, comprising a second container; and an intermediate element, comprising a first action end and a second action end, wherein the first action end and the second action end are disposed in the first container and the second container, respectively, wherein when the second element is moved relatively to the first element, a first control volume is formed in the first container between an end of the first element and the first action end of the intermediate element, and a second control volume is formed in the second container between an end of the second element and the second action end of the intermediate element, wherein the first control volume in the first container of the first element has a first pressure, the second control volume in the second container of the second element has a second pressure, and the ratio of the first pressure to the second pressure is a predetermined ratio, and when one of the second control volume in the second container of the second element and the first control volume in the first container of the first element is varied, automatic pressure compensation happens on the other one of the second control volume in the second container of the second element and the first control volume in the first container of the first element, so that the varied first control volume in the first container of the first element has the first pressure, the varied second control volume in the second container of the second element has the second pressure, and the predetermined ratio of the first pressure to the second pressure is maintained.
 5. The suction device as claimed in claim 4, wherein the predetermined ratio is the ratio of a second sectional area of the second action end of the intermediate element to a first sectional area of the first action end of the intermediate element.
 6. The suction device as claimed in claim 4, further comprising: a suction plate, communicated with the first container of the first element or the second container of the second element, wherein the first pressure of the first control volume or the varied first control volume in the first container of the first element or the second pressure of the second control volume or the varied second control volume in the second container of the second element produces a suction action on an object via the suction plate.
 7. A suction device, comprising: a first element, comprising a first container; a second element, comprising a second container communicated with the first container of the first element; and an intermediate element, comprising a first action end and a second action end, wherein the first action end and the second action end are disposed in the first container and the second container, respectively, wherein when the second element is moved relatively to the first element, a first control volume is formed in the first container between an end of the first element and the first action end of the intermediate element, and a second control volume is formed in the second container between an end of the second element and the second action end of the intermediate element, wherein the first control volume in the first container of the first element has a first pressure, the second control volume in the second container of the second element has a second pressure, and the ratio of the first pressure to the second pressure is a predetermined ratio, and when the second control volume in the second container of the second element is varied, automatic pressure compensation happens on the first control volume in the first container of the first element, so that a varied first control volume in the first container of the first element has the first pressure, a varied second control volume in the second container of the second element has the second pressure, and the predetermined ratio of the first pressure to the second pressure is maintained.
 8. The suction device as claimed in claim 7, wherein the predetermined ratio is the ratio of a second sectional area of the second action end of the intermediate element to a first sectional area of the first action end of the intermediate element.
 9. The suction device as claimed in claim 7, further comprising: a suction plate, communicated with the first control volume in the first container of the first element, wherein the first pressure of the first control volume in the first container of the first element produces a suction action on an object via the suction plate.
 10. The suction device as claimed in claim 9, further comprising: a valve element, disposed between the first control volume of the first container of the first element and the suction plate. 